Method of forming chromium nitride layer and structure including the chromium nitride layer

ABSTRACT

Methods and systems for depositing chromium nitride layers onto a surface of the substrate and structures and devices formed using the methods are disclosed. An exemplary method includes using a deposition process, depositing a chromium nitride layer onto a surface of the substrate. The deposition process can include providing a chromium precursor to the reaction chamber and separately providing a nitrogen reactant to the reaction chamber. The deposition process may be a thermal cyclical deposition process.

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 63/014,038 filed Apr. 22, 2020 titled “METHOD OF FORMINGCHROMIUM NITRIDE LAYER AND STRUCTURE INCLUDING THE CHROMIUM NITRIDELAYER,” and U.S. Provisional Patent Application Ser. No. 63/010,560filed Apr. 15, 2020 titled “METHOD OF FORMING CHROMIUM NITRIDE LAYER ANDSTRUCTURE INCLUDING THE CHROMIUM NITRIDE LAYER,” the disclosures ofwhich are hereby incorporated by reference in their entirety.

FIELD OF INVENTION

The present disclosure generally relates to methods and systems suitablefor forming a layer on a surface of a substrate and to structuresincluding the layer. More particularly, the disclosure relates tomethods and systems for forming layers that include chromium nitride andto structures formed using the methods and systems.

BACKGROUND OF THE DISCLOSURE

The scaling of semiconductor devices, such as, for example,complementary metal-oxide-semiconductor (CMOS) devices, has led tosignificant improvements in speed and density of integrated circuits.However, conventional device scaling techniques face significantchallenges for future technology nodes.

For example, one challenge has been finding a suitable conductingmaterial for use as a gate electrode in the CMOS devices. CMOS deviceshave conventionally used n-type doped polysilicon as the gate electrodematerial. However, doped polysilicon may not be an ideal gate electrodematerial for advanced node applications. Although doped polysilicon isconductive, there may still be a surface region which can be depleted ofcarriers under bias conditions. This region may appear as an extra gateinsulator thickness, commonly referred to as gate depletion, and maycontribute to the equivalent oxide thickness. While the gate depletionregion may be thin, on the order of a few angstroms (Å), the gatedepletion region may become significant as the gate oxide thicknessesare reduced in advanced node applications. As a further example,polysilicon does not exhibit an ideal effective work function (eWF) forboth NMOS and PMOS devices. To overcome the non-ideal effective workfunction of doped polysilicon, a threshold voltage adjustmentimplantation may be utilized. However, as device geometries reduce inadvanced node applications, the threshold voltage adjustmentimplantation processes may become increasingly complex and impractical.

To overcome problems associated with doped polysilicon gate electrodes,polysilicon gate material may be replaced with an alternative material,such as, for example, a titanium nitride layer. The titanium nitridelayer may provide a more ideal effective work function for CMOSapplications. However, in some cases, where higher work function valuesthan those obtained with titanium nitride layers—e.g., in PMOS regionsof a CMOS device—are desired, improved materials for gate electrodes aredesired. Such materials may also be suitable for otherelectrode/capacitor applications, such as dynamic random access memory(DRAM) applications, as well as other applications.

Any discussion, including discussion of problems and solutions, setforth in this section has been included in this disclosure solely forthe purpose of providing a context for the present disclosure. Suchdiscussion should not be taken as an admission that any or all of theinformation was known at the time the invention was made or otherwiseconstitutes prior art.

SUMMARY OF THE DISCLOSURE

This summary may introduce a selection of concepts in a simplified form,which may be described in further detail below. This summary is notintended to necessarily identify key features or essential features ofthe claimed subject matter, nor is it intended to be used to limit thescope of the claimed subject matter.

Various embodiments of the present disclosure relate to methods offorming structures including chromium nitride layers, to structures anddevices formed using such methods, and to apparatus for performing themethods and/or for forming the structures and/or devices. While the waysin which various embodiments of the present disclosure address drawbacksof prior methods and systems are discussed in more detail below, ingeneral, various embodiments of the disclosure provide improved methodsof forming chromium nitride layers that exhibit relatively high workfunction values. Additionally or alternatively, chromium nitride layerscan be formed using one or more chromium precursors. Further, exemplarychromium nitride layers can be formed using a thermal cyclicaldeposition process—without using a plasma or plasma-activated species.Alternatively, a process using plasma or plasma-activated species can beutilized. If such a process is used, the plasma may be N₂ plasma, N₂/H₂plasma or NH₃ plasma.

In accordance with exemplary embodiments of the disclosure, a method offorming a gate electrode structure is disclosed. Exemplary methods offorming the gate electrode structure include providing a substratewithin a reaction chamber of a reactor and, using a deposition process,depositing a chromium nitride layer onto a surface of the substrate. Thedeposition process can include (e.g., sequentially and separately)providing a chromium precursor to the reaction chamber and providing anitrogen reactant to the reaction chamber. The chromium precursor caninclude one or more of a chromium amidinate precursor, chromium amidoprecursor, chromium diazadiene precursor, chromium cyclopentadienylprecursor, chromium zero valent precursor, chromium oxyhalide precursor,chromium beta-diketonate precursor, chromium aminoalkoxide precursor,chromium iminoalkoxide precursor, chromium alkoxyalkoxide precursor anda heteroleptic chromium precursor. The chromium can be selected from thegroup consisting of chromium fluoride, chromium chloride, chromiumbromide, chromium iodide, and the like. The chromium oxyhalide can beselected from the group consisting of a chromium oxyfluoride, a chromiumoxychloride, a chromium oxybromide, a chromium oxyiodide, and the like.The nitrogen reactant can be selected from one or more of ammonia (NH₃),hydrazine (N₂H₄), other nitrogen and hydrogen-containing gases, and thelike. The deposition process may be cyclical. The cyclical depositionprocess can include one or more of an atomic layer deposition processand a cyclical chemical vapor deposition process. The cyclicaldeposition process can include a thermal process—i.e., a process thatdoes not use plasma-activated species. Use of a thermal process may bedesirable for some applications, such as formation of gate structures,because use of plasma for such applications may be detrimental to deviceperformance.

In accordance with further exemplary embodiments of the disclosure, amethod of forming a structure comprising a chromium nitride layerincludes providing a substrate within a reaction chamber of a reactorand, using a thermal cyclical deposition process, depositing a layercomprising chromium nitride onto a surface of the substrate. The thermalcyclical deposition process can include providing a chromium precursorto the reaction chamber and providing a nitrogen reactant to thereaction chamber. The chromium precursor and the nitrogen reactant canbe the same or similar to the chromium precursor and the nitrogenreactant described above and elsewhere herein. In accordance withexamples of the disclosure, the thermal cyclical deposition process doesnot include use of a nitrogen plasma, does not include use of excitednitrogen species, does not include use of nitrogen radicals, and/or doesnot include use of diatomic nitrogen as a nitrogen reactant.

In accordance with yet further exemplary embodiments of the disclosure,a structure is formed using a method as described herein. The structurecan include a substrate and a chromium nitride layer formed overlying asurface of the substrate. Exemplary structures can further include oneor more additional layers, such as an additional metal or conductinglayer overlying the chromium nitride layer. The structure can be or formpart of a CMOS structure, such as one or more of a PMOS and NMOSstructure.

In accordance with yet additional embodiments of the disclosure, adevice or portion thereof can be formed using a method and/or astructure as described herein. The device can include a substrate, aninsulating or dielectric layer, a chromium nitride layer overlying theinsulating or dielectric layer, and optionally an additional metal layeroverlying the chromium nitride layer. The device can be or form part ofa CMOS device.

In accordance with yet additional examples of the disclosure, a systemto perform a method as described herein and/or to form a structure,device, or portion of either, is disclosed.

These and other embodiments will become readily apparent to thoseskilled in the art from the following detailed description of certainembodiments having reference to the attached figures. The invention isnot being limited to any particular embodiments disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A more complete understanding of the embodiments of the presentdisclosure may be derived by referring to the detailed description andclaims when considered in connection with the following illustrativefigures.

FIG. 1 illustrates a method in accordance with exemplary embodiments ofthe disclosure.

FIG. 2 illustrates a structure/device portion in accordance withexemplary embodiments of the disclosure.

FIG. 3 illustrates a reactor system in accordance with additionalexemplary embodiments of the disclosure.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The description of exemplary embodiments of methods, structures, devicesand systems provided below is merely exemplary and is intended forpurposes of illustration only; the following description is not intendedto limit the scope of the disclosure or the claims. Moreover, recitationof multiple embodiments having stated features is not intended toexclude other embodiments having additional features or otherembodiments incorporating different combinations of the stated features.For example, various embodiments are set forth as exemplary embodimentsand may be recited in the dependent claims. Unless otherwise noted, theexemplary embodiments or components thereof may be combined or may beapplied separate from each other.

As set forth in more detail below, various embodiments of the disclosureprovide methods for forming structures, such as gate electrodestructures. Exemplary methods can be used to, for example, form CMOSdevices or portions thereof. The method according to the currentdisclosure may be used to produce a structure comprising the chromiumnitride layer and a device comprising the chromium nitride layer. Thechromium nitride layer according to the current disclosure may be usedas work function metal in metal gates, liner/barrier, metal electrode(DRAM, Logic, 3DNAND) and also p-metal gate for logic and also as adipole (p) tuning layer for logic and other applications. However,unless noted otherwise, the invention is not necessarily limited to suchexamples.

Further, exemplary methods can include forming a chromium nitride layerusing a cyclical deposition process. In accordance with examples of thedisclosure, a (e.g., thermal) cyclical deposition process includesproviding a chromium precursor to the reaction chamber and providing anitrogen reactant to the reaction chamber. In accordance with theseexamples, no activated species, such as radicals, ions, or the like, areformed using a plasma.

In this disclosure, “gas” can include material that is a gas at normaltemperature and pressure (NTP), a vaporized solid and/or a vaporizedliquid, and can be constituted by a single gas or a mixture of gases,depending on the context. A gas other than the process gas, i.e., a gasintroduced without passing through a gas distribution assembly, othergas distribution device, or the like, can be used for, e.g., sealing thereaction space, and can include a seal gas, such as a rare gas. In somecases, the term “precursor” can refer to a compound that participates inthe chemical reaction that produces another compound, and particularlyto a compound that constitutes a film matrix or a main skeleton of afilm; the term “reactant” can be used interchangeably with the termprecursor. The term “inert gas” can refer to a gas that does not takepart in a chemical reaction and/or does not become a part of a filmmatrix to an appreciable extent. Exemplary inert gases include He and Arand any combination thereof. In some cases, nitrogen and/or hydrogen canbe an inert gas. Gas used for purging, i.e. a purge gas, may be an inertgas.

As used herein, the term “substrate” can refer to any underlyingmaterial or materials that can be used to form, or upon which, a device,a circuit, or a film can be formed. A substrate can include a bulkmaterial, such as silicon (e.g., single-crystal silicon), other Group IVmaterials, such as germanium, or other semiconductor materials, such asa Group II-VI or Group III-V semiconductor materials, and can includeone or more layers overlying or underlying the bulk material. Further,the substrate can include various features, such as recesses,protrusions, and the like formed within or on at least a portion of alayer of the substrate. By way of examples, a substrate can include bulksemiconductor material and an insulating or dielectric material layeroverlying at least a portion of the bulk semiconductor material.

As used herein, the term “film” and/or “layer” can refer to anycontinuous or non-continuous structure and material, such as materialdeposited by the methods disclosed herein. For example, film and/orlayer can include two-dimensional materials, three-dimensionalmaterials, nanoparticles or even partial or full molecular layers orpartial or full atomic layers or clusters of atoms and/or molecules. Afilm or layer may comprise material or a layer with pinholes, which maybe at least partially continuous.

As used herein, a “structure” can be or include a substrate as describedherein. Structures can include one or more layers overlying thesubstrate, such as one or more layers formed according to a method asdescribed herein.

The term “cyclic deposition process” or “cyclical deposition process”can refer to the sequential introduction of precursors (and/orreactants) into a reaction chamber to deposit a layer over a substrateand includes processing techniques such as atomic layer deposition(ALD), cyclical chemical vapor deposition (cyclical CVD), and hybridcyclical deposition processes that include an ALD component and acyclical CVD component.

The term “atomic layer deposition” can refer to a vapor depositionprocess in which deposition cycles, typically a plurality of consecutivedeposition cycles, are conducted in a process chamber. The term atomiclayer deposition, as used herein, is also meant to include processesdesignated by related terms, such as chemical vapor atomic layerdeposition, when performed with alternating pulses ofprecursor(s)/reactive gas(es), and purge (e.g., inert carrier) gas(es).

Generally, for ALD processes, during each cycle, a precursor isintroduced to a reaction chamber and is chemisorbed to a depositionsurface (e.g., a substrate surface that can include a previouslydeposited material from a previous ALD cycle or other material), formingabout a monolayer or sub-monolayer of material that does not readilyreact with additional precursor (i.e., a self-limiting reaction).Thereafter, in some cases, a reactant (e.g., another precursor orreaction gas) may subsequently be introduced into the process chamberfor use in converting the chemisorbed precursor to the desired materialon the deposition surface. The reactant can be capable of furtherreaction with the precursor. Purging steps can be utilized during one ormore cycles, e.g., during each step of each cycle, to remove any excessprecursor from the process chamber and/or remove any excess reactantand/or reaction byproducts from the reaction chamber.

As used herein, a “chromium nitride layer” can be a material layer thatcan be represented by a chemical formula that includes chromium andnitrogen. A chromium nitride layer can include additional elements, suchas oxygen (e.g., a chromium oxynitride layer), carbon (chromiumcarbonitride), and the like. In other words, the chromium nitride layermay comprise Cr_(x)N_(y)C_(z) or Cr_(x)N_(y)O_(z).

As used herein, a “chromium precursor” includes a gas or a material thatcan become gaseous and that can be represented by a chemical formulathat includes chromium.

The term “nitrogen reactant” can refer to a gas or a material that canbecome gaseous and that can be represented by a chemical formula thatincludes nitrogen. In some cases, the chemical formula includes nitrogenand hydrogen. In some cases, the nitrogen reactant does not includediatomic nitrogen. Examples of nitrogen reactants include compounds ofthe general formula R₂NNR₂, where each R is independently one of thefollowing: H, Me, Et, iPr, tBu, Ph, Bz, SiMe₃, Cy. Additionally, R mayrepresent other alkyl, aryl or silyl substituents.

Further, in this disclosure, any two numbers of a variable canconstitute a workable range of the variable, and any ranges indicatedmay include or exclude the endpoints. Additionally, any values ofvariables indicated (regardless of whether they are indicated with“about” or not) may refer to precise values or approximate values andinclude equivalents, and may refer to average, median, representative,majority, or the like. Further, in this disclosure, the terms“including,” “constituted by” and “having” refer independently to“typically or broadly comprising,” “comprising,” “consisting essentiallyof,” or “consisting of” in some embodiments. In this disclosure, anydefined meanings do not necessarily exclude ordinary and customarymeanings in some embodiments.

Turning now to the figures, FIG. 1 illustrates a method 100 inaccordance with exemplary embodiments of the disclosure. Method 100 canbe used to, for example, form a gate electrode structure suitable forNMOS, PMOS, and/or CMOS devices. However, unless otherwise noted,methods are not limited to such applications.

Method 100 includes the steps of providing a substrate within a reactionchamber of a reactor (step 102) and using a deposition process,depositing a layer comprising chromium nitride onto a surface of thesubstrate (step 104).

During step 102, a substrate is provided within a reaction chamber. Thereaction chamber used during step 102 can be or include a reactionchamber of a chemical vapor deposition reactor system configured toperform a deposition process. The deposition process may be cyclical. Inan embodiment, the deposition process is a cyclical deposition process.Further, in an embodiment, providing a chromium precursor to thereaction chamber and providing a nitrogen reactant to the reactionchamber are separated by a purge step. The embodiment comprising a purgestep may be a cyclical deposition process. The reaction chamber can be astand-alone reaction chamber or part of a cluster tool.

Step 102 can include heating the substrate to a desired depositiontemperature within the reaction chamber. In some embodiments of thedisclosure, step 102 includes heating the substrate to a temperature ofless than 800° C. For example, in some embodiments of the disclosure,heating the substrate to a deposition temperature may comprise heatingthe substrate to a temperature between approximately 20° C. andapproximately 800° C., or between approximately 100° C. and 600° C., orbetween approximately 200° C. and 500° C. In addition to controlling thetemperature of the substrate, a pressure within the reaction chamber mayalso be regulated. For example, in some embodiments of the disclosure,the pressure within the reaction chamber during step 102 may be lessthan 760 Torr or between 0.001 Torr and 760 Torr, or between 0.1 Torrand 760 Torr, or between 10 Torr and 760 Torr, or between 50 Torr and760 Torr.

During step 104, a chromium nitride layer is deposited onto a surface ofthe substrate using a deposition process. As noted above, the depositionprocess can include cyclical CVD, ALD, or a hybrid cyclical CVD/ALDprocess. For example, in some embodiments, the growth rate of aparticular ALD process may be low compared with a CVD process. Oneapproach to increase the growth rate may be that of operating at ahigher deposition temperature than that typically employed in an ALDprocess, resulting in some portion of a chemical vapor depositionprocess, but still taking advantage of the sequential introduction ofreactants. Such a process may be referred to as cyclical CVD. In someembodiments, a cyclical CVD process may comprise the introduction of twoor more reactants into the reaction chamber, wherein there may be a timeperiod of overlap between the two or more reactants in the reactionchamber resulting in both an ALD component of the deposition and a CVDcomponent of the deposition. This is referred to as a hybrid process.For example, a cyclical deposition process may comprise the continuousflow of one reactant and the periodic pulsing of a second reactant intothe reaction chamber.

In accordance with examples of the disclosure, the cyclical depositionprocess may be a thermal deposition process. In these cases, thecyclical deposition process does not include use of a plasma to formactivated species for use in the cyclical deposition process. Forexample, the cyclical deposition process may not comprise formation oruse of a nitrogen plasma, may not comprise formation or use of excitednitrogen species, and/or may not comprise formation or use or nitrogenradicals. In an embodiment, the deposition process comprises thecontinuous flow of at least one precursor/reactant.

The cyclical deposition process can include (e.g., separately and/orsequentially) providing a chromium precursor to the reaction chamber andproviding a nitrogen reactant to the reaction chamber. The chromiumprecursor can include one or more of a chromium amidinate precursor, achromium amido precursor and a chromium diazadiene precursor.

The chromium amidinate precursors may be, for example, Cr(iPrFMD)_(x),Cr(tBuFMD)_(x), Cr(iPrAMD)_(x) or Cr(tBuAMD)_(x), where x=2 or 3. As iscommon in the art, FMD stands for a formamidinate ligand, and AMD for anacetamidinate ligand. The chromium amido precursor may be, for exampleCr[N(iPr)₂]₃, Cr[N(SiMe₃)₂]₃. Other similarly substituted variants canbe envisaged. The chromium diazadiene precursor may be, for example,Cr(tBu₂DAD)₂, Cr(tBu₂DAD)₃, Cr(iPr₂DAD)₃ or Cr(iPr₂DAD)₃. Also othersubstituted DAD ligands can be envisaged.

The chromium precursor may include also one or more cyclopentadienylprecursors or zero valent precursors. Chromium cyclopentadienylprecursor may be, for example, CrCp₂, Cr(MeCp)₂, Cr(EtCp)₂, Cr(iPrCp)₂,Cr(tBuCp)₂, Cr(nBuCp)₂, Cr(Me₅Cp)₂ and Cr(Me₄Cp)₂. The chromiumcyclopentadienyl precursor may also be another similarly substitutedvariant. Chromium zero valent precursor may be, for example,Cr(η⁶-benzene)(CO)₃, Cr(CO)₆, Cr(η⁶-benzene)₂, or other variant wherethe benzene ligand has one to six alkyl substituents.

The chromium precursor may be a chromium oxyhalide precursor. By way ofexamples, the chromium oxyhalide can be selected from one or more ofchromium oxyhalides, such as one or more of a chromium oxyfluoride, achromium oxychloride, a chromium oxybromide, and a chromium oxyiodide.The chromium oxyhalide can include only chromium, oxygen, and one ormore halides. By way of example, the chromium oxyhalide can includechromium oxytrichloride or the like.

Further, chromium precursor may be an alkoxyalkoxide precursor of theformula Cr(R′R″COCH₂OR)_(x), where R, R′, and R″ can independently beany alkyl or aryl group, including Me, Et, nPr, iPr, nBu, sBu, tBu, Cy,Ph, Bz, and where x=2 or 3. Chromium precursor may also bebeta-diketonate precursor, such as Cr(acac)_(x), Cr(thd)_(x),Cr(hfac)_(x), where x=2 or 3. As common in the art, acac stands foracetylacetonate, thd for 1,1,6,6-tetramethylheptandionate and hfac forhexaflouroacetylacetonate. Still further, chromium precursor may also bean aminoalkoxide precursor or an iminoalkoxide precursor, such asCr(R′R″COCH₂NR₂)_(x), Cr(R′R″COCHNR)_(x), where each of R, R′, and R″can independently be any alkyl or aryl group, including Me, Et, nPr,iPr, nBu, sBu, tBu, Cy, Ph, Bz, and where x=2 or 3.

Also heteroleptic chromium precursors, comprising a combination of twoor more different precursor types described above, may be used. Forexample, two, three or four different precursor types can be used.Examples of heteroleptic chromium precursors are CrO₂(acac)₂,CrCp(tBu₂DAD), and Cr(EtCp)(iPrAMD)₂.

The nitrogen reactant can be or include one or more of ammonia (NH₃),hydrazine (N₂H₄), or the like. Examples of hydrazine reactants includecompounds of the general formula R₂NNR₂, where each R is independentlyone of the following: H, Me, Et, iPr, tBu, Ph, Bz, SiMe₃, Cy.Additionally, R may represent other alkyl, aryl or silyl substituents.The nitrogen reactant can include or consist of nitrogen and hydrogen.In some cases, the nitrogen reactant does not include diatomic nitrogen.In the case of thermal cyclical deposition processes, a duration of thestep of providing nitrogen reactant to the reaction chamber can berelatively long to allow the nitrogen reactant to react with theprecursor or a derivative thereof. For example, the duration can begreater than or equal to 5 seconds or greater than or equal to 10seconds or between about 5 and 10 seconds.

As part of step 104, the reaction chamber can be purged using a vacuumand/or an inert gas, to mitigate gas phase reactions between reactantsand enable self-saturating surface reactions—e.g., in the case of ALD.Additionally or alternatively, the substrate may be moved to separatelycontact a first vapor phase reactant and a second vapor phase reactant.Surplus chemicals and reaction byproducts, if any, can be removed fromthe substrate surface or reaction chamber, such as by purging thereaction space or by moving the substrate, before the substrate iscontacted with the next reactive chemical. The reaction chamber can bepurged after the step of providing a chromium precursor to the reactionchamber and/or after the step of providing a nitrogen reactant to thereaction chamber.

In some embodiments of the disclosure, method 100 includes repeating aunit deposition cycle that includes (1) providing a chromium precursorto the reaction chamber and (2) providing a nitrogen reactant to thereaction chamber, with optional purge or move steps after step (1)and/or (2). The deposition cycle can be repeated one or more times,based on, for example, desired thickness of the chromium nitride layer.For example, if the thickness of the chromium nitride layer is less thandesired for a particular application, then the step of providing achromium precursor to the reaction chamber and providing a nitrogenreactant to the reaction chamber can be repeated one or more times. Oncethe chromium nitride layer has been deposited to a desired thickness,the substrate can be subjected to additional processes to form a devicestructure and/or device.

In some embodiments, a step coverage of the chromium nitride layer isequal to or greater than about 50%, or greater than about 80%, orgreater than about 90%, or about 95%, or about 98%, or about 99% orgreater, in/on structures having aspect ratios (height/width) of morethan about 2, more than about 5, more than about 10, more than about 25,more than about 50, or even more than about 100.

FIG. 2 illustrates a structure/a portion of a device 200 in accordancewith additional examples of the disclosure. The portion of a device orstructure 200 includes a substrate 202, dielectric or insulatingmaterial 204, and chromium nitride layer 206. In the illustratedexample, structure 200 also includes an additional conducting layer 212.

Substrate 202 can be or include any of the substrate material describedherein. In the illustrated example, substrate 202 includes a sourceregion 214, a drain region 216, and a channel region 218. Althoughillustrated as a horizontal structure, structures and devices inaccordance with examples of the disclosure can include vertical and/orthree-dimensional structures and devices, such as FinFET devices, gateall around devices and nanosheet devices.

Dielectric or insulating material 204 can include one or more dielectricor insulating materials suitable for gate structure applications. By wayof example, dielectric or insulating material 204 can include aninterface layer 208 and a high-k material 210 deposited overlyinginterface layer 208. In some cases, interface layer 208 may not exist ormay not exist to an appreciable extent. Interface layer 208 can includean oxide, such as a silicon oxide, which can be formed on a surface ofthe substrate 202 using, for example a chemical oxidation process or anoxide deposition process. High-k material 210 can be or include, forexample, a metallic oxide having a dielectric constant greater thanapproximately 7. In some embodiments, the high-k material includes has adielectric constant higher than the dielectric constant of siliconoxide. Exemplary high-k materials include one or more of hafnium oxide(HfO₂), tantalum oxide (Ta₂O₅), zirconium oxide (ZrO₂), titanium oxide(TiO₂), hafnium silicate (HfSiO_(x)), aluminum oxide (Al₂O₃) orlanthanum oxide (La₂O₃), or mixtures/laminates thereof.

Chromium nitride layer 206 can be formed according to a method describedherein. When chromium nitride layer 206 is formed using a cyclicaldeposition process, a concentration of chromium and/or nitrogen can varyfrom a bottom of chromium nitride layer 206 to a top of chromium nitridelayer 206 by, for example, controlling an amount of chromium precursorand/or nitrogen reactant and/or respective pulse times during one ormore deposition cycles. In some cases, chromium nitride layer 206 canhave a stochiometric composition. A work function and other propertiesof chromium nitride layer 206 can be altered by altering an amount ofnitrogen and/or chromium in the layer or in a deposition cycle.

Chromium nitride layer 206 can include oxygen. For example, chromiumnitride layer 206 can be or include a chromium oxynitride layer.Chromium nitride layer 206 can include impurities, such as halides,hydrogen or the like in an amount of less than one atomic percent, lessthan 0.2 atomic percent, or less than about 0.1 atomic percent, or lessthan 0.05 atomic percent, alone or combined.

A work function of chromium nitride layer 206 can be >4.6 eV, >4.7eV, >4.8 eV, >4.9 eV, >4.95 eV, or >5.0 eV. Additionally oralternatively, chromium nitride layer 206 can form a continuousfilm—e.g., using method 100—at a thickness of less than <5 nm, <4 nm, <3nm, <2 nm, <1.5 nm, <1.2 nm, <1.0 nm, or <0.9 nm. Chromium nitride layer206 can be relatively smooth, with relatively low grain boundaryformation. In some cases, chromium nitride layer 206 may be amorphous,with relatively low columnar crystal structures (as compared to TiN).RMS roughness of exemplary chromium nitride layer 206 can be <1.0 nm,<0.7 nm, <0.5 nm, <0.4 nm, <0.35 nm, <0.3 nm, at a thickness of lessthan 10 nm.

Additional conducting layer 212 can include, for example, metal, such asa refractory metal or the like.

FIG. 3 illustrates a system 300 in accordance with yet additionalexemplary embodiments of the disclosure. System 300 can be used toperform a method as described herein and/or form a structure or deviceportion as described herein.

In the illustrated example, system 300 includes one or more reactionchambers 302, a precursor gas source 304, a nitrogen reactant gas source306, a purge gas source 308, an exhaust source 310, and a controller312.

Reaction chamber 302 can include any suitable reaction chamber, such asan ALD or CVD reaction chamber.

Precursor gas source 304 can include a vessel and one or more chromiumprecursors as described herein—alone or mixed with one or more carrier(e.g., inert) gases. Nitrogen reactant gas source 306 can include avessel and one or more nitrogen reactants as described herein—alone ormixed with one or more carrier gases. Purge gas source 308 can includeone or more inert gases as described herein. Although illustrated withthree gas sources 304-308, system 300 can include any suitable number ofgas sources. Gas sources 304-308 can be coupled to reaction chamber 302via lines 314-318, which can each include flow controllers, valves,heaters, and the like. Exhaust source 310 can include one or more vacuumpumps.

Controller 312 includes electronic circuitry and software to selectivelyoperate valves, manifolds, heaters, pumps and other components includedin the system 300. Such circuitry and components operate to introduceprecursors, reactants, and purge gases from the respective sources304-308. Controller 312 can control timing of gas pulse sequences,temperature of the substrate and/or reaction chamber, pressure withinthe reaction chamber, and various other operations to provide properoperation of the system 300. Controller 312 can include control softwareto electrically or pneumatically control valves to control flow ofprecursors, reactants and purge gases into and out of the reactionchamber 302. Controller 312 can include modules such as a software orhardware component, e.g., a FPGA or ASIC, which performs certain tasks.A module can advantageously be configured to reside on the addressablestorage medium of the control system and be configured to execute one ormore processes.

Other configurations of system 300 are possible, including differentnumbers and kinds of precursor and reactant sources and purge gassources. Further, it will be appreciated that there are manyarrangements of valves, conduits, precursor sources, and purge gassources that may be used to accomplish the goal of selectively feedinggases into reaction chamber 302. Further, as a schematic representationof a system, many components have been omitted for simplicity ofillustration, and such components may include, for example, variousvalves, manifolds, purifiers, heaters, containers, vents, and/orbypasses.

During operation of reactor system 300, substrates, such assemiconductor wafers (not illustrated), are transferred from, e.g., asubstrate handling system to reaction chamber 302. Once substrate(s) aretransferred to reaction chamber 302, one or more gases from gas sources304-308, such as precursors, reactants, carrier gases, and/or purgegases, are introduced into reaction chamber 302.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Indeed, variousmodifications of the disclosure, in addition to those shown anddescribed herein, such as alternative useful combinations of theelements described, may become apparent to those skilled in the art fromthe description. Such modifications and embodiments are also intended tofall within the scope of the appended claims.

1. A method of forming a gate electrode structure, the method comprisingthe steps of: providing a substrate within a reaction chamber of areactor; and depositing a chromium nitride layer onto a surface of thesubstrate, wherein the deposition process comprises: providing achromium precursor to the reaction chamber; and providing a nitrogenreactant to the reaction chamber.
 2. The method of claim 1, wherein thechromium precursor comprises one or more of a chromium amidinateprecursor, a chromium amido precursor and a chromium diazadieneprecursor.
 3. The method of claim 2, wherein the chromium amidinateprecursor is selected from the group consisting of Cr(iPrFMD)_(x),Cr(tBuFMD)_(x), Cr(iPrAMD)_(x), Cr(tBuAMD)_(x), where x=2 or
 3. 4. Themethod of claim 2, wherein the chromium amido precursor is selected fromthe group consisting of Cr[N(iPr)₂]₃, Cr[N(SiMe₃)₂]₃, and othersimilarly substituted variants.
 5. The method of claim 2, wherein thechromium diazadiene precursor is selected from the group consisting ofCr(tBu₂DAD)₂, Cr(tBu₂DAD)₃, Cr(iPr₂DAD)₃, Cr(iPr₂DAD)₃ and othersubstituted DAD ligands.
 6. The method of claim 1, wherein thedeposition process comprises the continuous flow of at least oneprecursor/reactant.
 7. The method of claim 1, wherein the depositionprocess is a cyclical deposition process.
 8. The method of claim 7,wherein the cyclical deposition process comprises an atomic layerdeposition process.
 9. The method of claim 7, wherein the cyclicaldeposition process comprises a cyclical chemical vapor depositionprocess.
 10. The method of claim 7, wherein providing a chromiumprecursor to the reaction chamber and providing a nitrogen reactant tothe reaction chamber are separated by a purge step.
 11. The method ofclaim 7, wherein the cyclical deposition process comprises a thermalprocess.
 12. The method of claim 7, wherein a duration of the step ofproviding the nitrogen reactant to the reaction chamber is greater thanor equal to 5 seconds, or greater than or equal to 10 seconds, orbetween about 5 seconds and about 10 seconds.
 13. The method of claim 1,wherein a temperature of the substrate within the reaction chamberduring the deposition process is between about 20° C. and about 800° C.14. The method of claim 1, wherein a pressure within the reactionchamber during the deposition process is less than 760 Torr.
 15. Themethod of claim 1, wherein the nitrogen reactant is selected from one ormore of ammonia (NH₃), hydrazine (N₂H₄), and other compounds comprisingor consisting of nitrogen and hydrogen.
 16. The method of claim 1,wherein the nitrogen reactant does not include diatomic nitrogen.
 17. Amethod of forming a structure comprising a chromium nitride layer, themethod comprising the steps of: providing a substrate within a reactionchamber of a reactor; and using a thermal deposition process, depositinga layer comprising chromium nitride onto a surface of the substrate,wherein the thermal deposition process comprises: providing a chromiumprecursor to the reaction chamber; and providing a nitrogen reactant tothe reaction chamber.
 18. The method of claim 17, wherein the chromiumprecursor comprises one or more of a chromium amidinate precursor, achromium amido precursor and a chromium diazadiene precursor.
 19. Themethod of claim 17, wherein the nitrogen reactant is selected from oneor more of ammonia (NH₃), hydrazine (N₂H₄), and other compoundscomprising or consisting of nitrogen and hydrogen.
 20. The method ofclaim 17, wherein the nitrogen reactant does not include diatomicnitrogen.
 21. The method of claim 17, wherein the thermal cyclicaldeposition process comprises one or more of a cyclical chemical vapordeposition process and an atomic layer deposition process.
 22. Themethod of claim 1, wherein the thermal cyclical deposition process doesnot comprise use of a nitrogen plasma.
 23. The method of claim 1,wherein the thermal cyclical deposition process does not comprise use ofexcited nitrogen species.
 24. The method of any of claim 1, wherein thethermal cyclical deposition process does not comprise use of nitrogenradicals.
 25. A structure comprising a chromium nitride layer formedaccording to the method of claim
 1. 26. The structure of claim 25,wherein a work function of the chromium nitride layer is >4.6 eV, >4.7eV, >4.8 eV, >4.9 eV, >4.95 eV, or >5.0 eV.
 27. The structure of claim24, wherein a RMS roughness of the chromium nitride layer is <1.0 nm,<0.7 nm, <0.5 nm, <0.4 nm, <0.35 nm, or <0.3 nm at a thickness of lessthan 10 nm.
 28. The structure of claim 25, wherein the structure is workfunction metal in a metal gate, a liner/barrier, a metal electrode inDRAM, Logic or 3DNAND, a p-metal gate for logic, or a dipole (p) tuninglayer for logic or for another application.
 29. A system comprising: oneor more reaction chambers; a precursor gas source comprising a chromiumprecursor; a nitrogen reactant gas source; an exhaust source; and acontroller, wherein the controller is configured to control gas flowinto at least one of the one or more reaction chambers to form achromium nitride layer overlying a surface of a substrate using athermal cyclical deposition process.